Method of deoxidizing metal sheet edge portions



Aug. 21, 1951 A. KRONQUEST 2,565,137

METHOD OF DEOXIDIZING METAL SHEET EDGE PORTIONS 6 Sheets-Sheet 1 Original Filed Aug. 18, 1942 mvsurom fllfiredl. larongues? 1951 A. L. KRONQUEST 2,565,137

METHOD OF nsoxmzmc; METAL swam EDGE ponnous Original Filed Aug. is, 1942 6 Sheets-Sheet s \x w Y m w w E? INVENI'OK.

8" 1951 A. L. KRONQUEST 2,565,137

METHOD OF DEOXIDIZING METAL SHEET EDGE PORTIONS Original Filed Aug. 18, 1942 6 Sheets-Sheet 4 INVENTOR. fllFred J;- Aronquesfl 714441. 0 66RPM fiITOK/VEKS.

Afig- 21 195 A. 1.. KRONQUEST METHOD OF DEOXIDIZING METAL SHEET EDGE PORTIONS 6 Sheets-Sheet 5 ori inal Fi led Aug. 18, 1942 w N QNA Aug. 21, 1951 A. 1.. KRONQUEST 2,555,137

METHOD OF DEOXIDIZING METAL SHEET EDGE PORTIONS Original Filed Aug. 18, 1942 6 Sheets-Sheet 6 nwnvrok. iii/ed l. Mvnqueafi" Patented Aug. 21, 1951 METHOD OF DEOXIDIZING METAL SHEET EDGE PORTIONS Alfred L. Kronquest, Syracuse, N. Y., assignor to Continental Can Company, Inc., New York, N. Y., a corporation of New York Original application August 18, 1942, Serial No.

455,240, now Patent No. 2,450,669, dated Octoher 5, 1948. Divided and this application July 16, 1945, Serial No. 605,423

The invention relates generally to the art ofmanufacturing metallic receptacles and primarily seeks to provide a novel method of deoxidizing sheet or can body blank edge portions which are to be brought into contact in the formation of can body side seams. thereby to facilitate efllcient solder bonding of the side seams. This application constitutes a division of the copending parent application, Serial Number 455,240, filed by Alfred L. Kronquest on August 18, 1942, and issued October 5, 1948, bearing United States Patent Number 2,450,669.

It has been found dimcult and commercially impractical heretofore to make can bodies including solder bonded side seams from mild steel or black plate blanks. Perhaps the principal difficulty has been experienced because of the inability efliciently to solder black plate. It is well known that in order to solder black plate, the portions thereof to be soldered must be cleansed of oxidation and scale, for without such cleansing the solder will not properly adhere to the metal. Moreover, the soldering must be performed immediately after the surface cleansing because reoxidation takes place rapidly. Various methods have been tried in efforts to solve this problem, among them beingthat of applying protective coatings to previously cleansed portions of the plate, said coatings having the quality of facilitating, or at least not interfering with efficient soldering, and being intended to protect the cleansed surfaces against oxidation and scale accumulations prior to soldering. Such methods have considerable merit in that they permit temporary storage of the treated sheets or blanks before soldering, but all such methods of which I am aware have presented accompanying disadvantages because of the time and labor necessarily consumed in performance of the several method steps, or the complicated and space consuming nature of the apparatus necessary to be used in performance of said method steps.

It is therefore an object of the invention to provide a novel method of deoxidizing can body blank edge portions which is so simple and emcient as to be subject to practice in standard can body makers without any material slowing down of normal speed of operation or any great change in the overall size of such machines.

It is to be understood that while the invention comprehends incorporation of the body blank edge cleansing method steps as part of a complete novel method including the feeding of the untreated blanks from a supply, the treating of the'blanks and the formation thereof into can Claims. (CL 134-3) bodies, including solder bonding of the side seams, it resides also in the method steps of edge cleansing or deoxidizing the metal sheet or body blanks alone, or in other words, apart from the other steps in said complete can body forming method.

It is also to be understood that while the method comprising the invention is primarily designed for deoxidizing black plate sheets or body blanks, it is in no sense limited to operation upon black plate alone but can be employed with equal facility on other metallic plates whereon oxidation takes place, such as bonderized plates. Whatever the type of plate, when the invention is practiced in a standard body maker it will be customary. but not necessary, to operate upon blanks which have the usual protective coating thereon of lacquer or enamel or both, leaving bare only those marginal or edge portions which are to engage in the formation of the can body side seams.

Another object of the invention is to provide a novel method of forming a d'eoxidizing gas for use in deoxidizing metallic surface areas which consists in forcing air in widely dispersed form into and through a contained body of concentrated hydrochloric acid thereby to form hydrogen chloride gas.

Another object of the invention is to provide a novel method of deoxidizing can body blank edge portions so as to prepare them for eihcient solder bonding which consists in feeding the blanks, forming a confining chamber about the edge portions of the travelling blanks, and directing hydrogen chloride gas into the chamber.

Another object of the invention is to provide a novel method of the last stated character in which the additional steps of forming the blanks into can bodies in which the deoxidized edge portions engage in side seams, and the solder bonding of sald side seams are included so that the solder bonding takes place before reoxidation of the side seam forming edge portions can take place following the deoxidizing step.

Another object of the invention is to provide a novel method of the last stated character in which is included the step of wetting the blank edge portions before passing them through the deoxidizing chamber, and in which there is included the step of drawing air into the deoxidizing chamber in a manner for preventing escape of gas therefrom into the surrounding atmosphere.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more fully understood by following the detailed description, the appended claims and the several views illustrated in the accompanying drawings.

In the drawings:

Figure l is a fragmentary side elevation illustrating the invention as being practiced in a conventional form of can body maker, parts being broken away and in section.

Figure 2 is a fragmentary vertical cross section taken across the can body blank feedway of a conventional form of body maker having improved deoxidizing manifold structures mounted thereon, the section through the manifold at the right-hand side of the feedway being taken through the suction connection, and that at the left-hand side of the feedway through the deoxidizing gas delivery duct.

Figure 3 is an edge view of one of the deoxidizing manifolds employed in practicing the invention looking in the direction of the can body blank edge passing slotway therein, parts being broken away and shown in longitudinal section.

Figure 4 is an enlarged fragmentary vertical longitudinal section taken on the line 4-4 on Figure 2.

Figure 5 is an enlarged fragmentary vertical longitudinal section taken on the line 5-5 on Figure 2.

Figure 6 is an enlarged horizontal section taken on the line 66 on Figure 1.

Figure 7 is a somewhat diagrammatic side elevation illustrating another manner of practicing the invention in which the deoxidizing gas 18 formed by passing air through concentrated hydrochloric acid.

Figure 8 is a view similar to Figure l and illustrates another manner of practicing the invention in which the deoxidizing gas is formed by heating a concentrated hydrochloric acid and water mixture and in which the step of wetting the can body blank edge portions can be dispensed with.

Figures 9 and 9A when joined at the line A-A together comprise a diagrammatic view illustrating the succession of steps which result in the complete process of deoxidizing the can body blanks and forming them into can bodies having solder bonded side seams.

Figure 10 is a face view of a body blank having a protective coating thereon of lacquer or enamel, only those marginal or edge portions which are to be cleansed and subsequently engaged in the formation of can body side seams being left bare.

Figure 11 is a view of the reverse face of the blank shown in Figure 10.

Although not so liminted in scope, the invention is particularly adapted for being practiced directly in a standard form of can body maker. An example of standard body maker is the wellknown Troyer-Fox machine, a disclosure of which may be found in U. S. Letters Patent 1,772,820, issued to Troyer on August 12, 1900. In body makers of this type, body blanks are drawn one-by-one from a supply stack at the supply station and are then fed step-by-step through an idle station, a grain breaking station at which the blanks are fed laterally off the feed line, are curled so as to break the grain and facilitate subsequent shaping of the can bodies, and then returned to the feed line in which they are advanced step-by-step through an idle station, a slitting and notching station, then through folding stations at which hooks are formed at the lateral edges of the blanks intended to subse-' quently engage in the formation of side seams, and then through a fluxing station to the shaping or forming station at which the can bodies are formed. The formed can bodies then pass on to the solder bonding station at which the side seams are solder bonded. When the improved method herein disclosed is practiced directly in a body maker the apparatus employed in practicing the deoxidizing steps of the methed is installed directly after the grain breaking station and in advance of the notching station and the stations succeeding the same This position of installation is clearly illustrated in Figures 1 and 2 of the drawings, and the complete sequence of the body forming steps, from the initial feeding of the can body blanks to the completion of the can bodies by the solder bonding step, is diagrammatically illustrated in Figures 9 and 9A.

In the apparatus illustrated in Figures 1 through 6, 5 designates body maker framing structure, 6 the grain breaking station of the body maker, and I the notching station thereof. As previously stated, the can body blank deoxidizing apparatus is installed between the stations 6 and 1 in the manner clearly illustrated in Figures 1 and 2 of the drawings.

In this installation, side housings or frame extensions 8 are interposed between the grain breaking and notching stations 6 and I and provide for the support of extensions 9 of the regular can body blank feedways in the standard body maker structure. The can body blanks III are fed over these feedways by the usual reciprocating feed bars H. In practicing the method directly in a body maker two identical deoxidizing manifolds generally designated l2 are mounted in cooperative relation to the feedways, one at the right-hand side and one at the left as indicated in Figure 2. These manifolds are so formed that the marginal edge portions of the travelling can body blanks project therethrough and are deoxidized so that when these edge portions are subsequently brought into engagement in the formation of side seams they can be efiiciently solder bonded without interference by the oxidation and scale which existed thereon prior to the deoxidation in the passage through the manifolds l2.

Each manifold includes two flat bars l3 laid face upon face and having their opposed faces recessed so as to form between them a gas chamber H. The inwardly positioned opposed portions of the bars are shaped to form a slotway l5 therebetween in the manner clearly illustrated in Figures 2 and 3 of the drawings, the slotway being only slightly wider than the thickness of the can body blanks which are designed to pass therethrough. A spacer bar I5 serves as a spacer for the opposed bar l3 within the gas chamber l4, and each bar I6 is recessed as at I! to form gas passages and thereby avoid dividing the gas chamber into two separate chambers. This bar l6 also serves as an edge guide for the can body blanks I0, and definitely limits the distance to which the marginal edges of the can body blanks project into the respective gas chamber in the manner clearly illustrated in Figure 2. The recessed bars l3 form a sort of inner shell surrounding the gas chamber H.

The inner shell of each manifold is surrounded by an outer shell composed of upper and lower plates I8 which are held in spaced relation above and below theinner shell bars I3 by intermediate spacers l9 and by longitudinal edge plates 20 disposed along the outer edge of the respective manifold in the manner clearly illustrated in Figure 2. The spacing of the plates I! with relation to the bars l3 provides an air chamber 2| partially surrounding the inner shell and. gas chamber, each such air chamber being defined inwardly by closure bars 22 extending longitudinally in opposed relation at the inner edge of the respective manifold and having their opposed faces spaced apart to provide a slotway 23 aligning'and corresponding in function with the slotway |5 hereinbefore referred to. See Figures 2 and 3. The slotways l5 and 23 extend through the endsof the manifold so that the can body blanks can pass freely through the manifolds to have the marginal edge portions thereof deoxidized in the manifolds and then pass on through the various other stations of the body maker.

A bottom bar 24 is secured along the outer edge of each manifold l2, and slotted end closure plates 25 are provided for closing the ends of the gas and air chambers l4 and 2|.

It will be observed by reference to Figures 2,

I 4 and 5 of the drawings that each manifold is provided with an opening 26 extending through the bottom bar 24, the lower plate l8 and one bar l3 and providing a gas port 26 leading into the gas chamber I4. See Figure 4 and the lefthand side of Figure 2. Each manifold also has an opening extending through the bottom bar 24, the lower plate |8,both plates 2|] and both bars l3, and forming a suction port 21 as clearly illustrated in Figure 5 and at the right-hand side of Figure 2. Each manifold is suitably supported upon the side housing or frame portion 8 as by a bracket 28. See Figures 1 and 2.

A pump 29 is provided and has its intake connected by a suction duct 30 with the suction port 21, a gauge 2? being connected in this duct so as to visually indicate the amount of suction or vacuum being drawn in the air chamber 2|. A cut-off valve 32 may be interposed in the 'duct 36 if desired. The outlet of the pump is connected with a pressure pipe 33 having an adjustable choke valve therein, a depending leg being connected in the pressure pipe 33 in advance of the valve 34 and leading into a collectingsump 35 in which bits of solid matter and condensation may be collected.

The outlet from the valve is connected by a duct 36 with a vessel 31 having water 38 therein. The vessel is closed by a rubber stopper 39 and an outlet to atmosphere also is supported in the stopper as indicated at 40. The duct 36 connects with atube 4| depending in the vessel 31 and which supports a porous walled hollow element 42 immersed in the water 36. The purpose of the valve 34 and the vessel 31 and its container parts will presently be described.

A tank 43 of compressed hydrogen chloride gas is provided in practicing this form of the method and the deoxidizing gas delivers from this tank through a suitable reducing valve 44 into a gas duct 45 connected with the gas port 26 in the manner clearly illustrated in Figures 1 and 2 of the drawings. The duct 45 has a valve casing 46 spliced therein, and within the casing there is mounted a valve plunger 41 having an annular recess 48 which is normally disposed to permit gas flow through the duct to the gas chamber M in the manifold in the manner illustrated in Figures 1 and 6 of the drawings. In order to normally hold-the valve plunger in the position stated there is provided another vertical leg 49 extending from the pressure pipe 33 and connecting in the casing 46 beneath the plunger valve. The pressure thus directed into the lower part of the casing 46 beneath the plunger valve serves to hold the valve in the open position illustrated in Figure 1 against the action of the compression spring 50 which constantly tends to move the plunger downwardly and close off the passage of gas through the duct 45. An air port 5| is provided in the top of the casing 46 so as to permit free upward movement of the plunger. It will be obvious that deoxidizing hydrogen chloride gas will be supplied through the duct 45 to the manifold gas chamber |4 so long as the pump 29 continues to operate. Whenever the pump 29 ceases to operate, thereby causing a failure of the suction or evacuation of the air chamber 2|, the pump will no longer supply pressure beneath the valve plunger 41 and the plunger will be moved downwardly by the spring 56 and discontinue the delivery of deoxidizing gas to the manifold gas chamber.

In passing toward the manifolds I2, the marginal edge portion of the can body blanks H! which are to be deoxidized in the manifolds pass between and are wetted by upper and lower swab sets 52 which are supported as at 53 on the-framing 8 andare supplied with wetting fluid from drip reservoirs 54 as indicated in Figure 1. Any suitable wetting fluid can be employed. as for example water plus .1 per cent wetting agent such as sulphonated fatty alcohol.

In practicing the method by employing apparatus constructed and installed as illustrated in Figures 1 through 6 the can body blanks are fed over the feedways 9 by the feeding devices H and the lateral marginal edge portions thereof pass between the wetting swabs 52 and are thoroughly wetted thereby. Immediately after being wetted by the swabs 52 the marginal edge portions of the travelling blanks pass into the manifolds I2 through the slotways I5 and 23 provided therein, being edge guided by the abutment bars I6. While passing through the gas chambers l4 the marginal edge portions of the body blanks will be treated by the gas in the chamber delivered by the duct 45 and will have all oxidation and scale removed therefrom: The constant drawing of air into the air spaces 2| through the slotways 23 and the drawing away of gas through the slotways l5 and air and gas from the air chambers 2| through the ducts 33 serves to prevent any of the hydrogen chloride gas from passing out into the atmosphere surrounding the manifolds l2. As previously stated, so long as the pumps 29 continue to operate and evacuate the chambers 2| and supply pressure in the vertical leg 49 the introduction of hydrogen chloride gas into the gas chamber M will continue, but whenever the pump ceases to operate the valve 46, 41 will act automatically to close off this introduction of gas and thereby assure against delivery of gas through the slotways l5 and 23 into the atmosphere surrounding the manifolds l2.

The choke valve 34 is adjusted so as to restrict the passage of air and gas through the pressure line 33 and 36 into the vessel 31 and assure the provision of a proper amount of pressure in the vertical leg 49 and below the valve plunger 41. The excess gas and air mixture passing through the Valve 34 and the duct 36 into the vessel 31 passes in widely dispersed form through the porous walled hollow element 42 into the water 36. The purpose of bubbling this gas and air mixture through the water 38 is tom-event free passage of the gas into the surrounding atmosphere and also to reclaim the gas. Hydrogen chloride is absorbed by the water and reforms into hydrochloric acid of commercial value. It has been found that the wetting of the marginal edge portions of the can body blanks before passing them into the deoxidizing manifolds l2 tremendously accelerates the action of the deoxidlzing gas upon the metal and brings about the desired deoxidation almost instantly.

It is to be understood that after the can body blank marginal edge portions have been cleansed, that is rendered devoid of'oxidation and scale, in the manner hereinbefore described, the blanks pass rapidly through the notching, hook forming, body shaping and seam forming and the solder bonding stations, thus completing the can bodies by the solder bonding step before any oxidation of the can body blank portions which were cleansed in the manifolds H can take place. As before stated, while it is preferred that the invention be practiced directly in the body maker as aforesaid, it is to be understood that the method can be practiced by use of apparatus separate and apart from the body maker and the deoxidizing steps followed by any approved method of protecting the deoxidized can body blank edge portions against reoxidation so that the blanks can be stored temporarily before the can bodies are actually made up therefrom.

In Figure 7 there is illustrated another form of apparatus by use of which the invention can be practiced and it is to be understood that the apparatus illustrated in this figure can be installed in the body maker in the manner illustrated in Figure 1 or employed apart from the body maker structure as desired. In this form of the apparatus a manifold structure generally designated 55 and'constructed in the manner illustrated in Figures 1 through of the drawings is employed. This manifold is connected by a suction duct 55 with the inlet to the pump 51, and the outlet of the pump is connected with a pressure line 58 including a sump connection 59 as and for the purposes previously described. The pressure line communicates through a choke valve 60 and a duct 5| with a gas reclaiming vessel 62 having water therein, as indicated at 53, and a porous walled hollow element 54 immersed in the water and through which the air and gas mixture delivered from the outlet pipe 58 are dispersed. In this form also the escape of hydrogen chloride to the atmosphere through the outlet '65 is prevented, the hydrogen chloride being absorbed by the water and reformed thereby into hydrochloric acid of commercial value.

In this form of the invention a novel manner of generating hydrogen chloride gas is employed. The construction provided by the adjustable choke valve 60 causes air under pressure to flow from the pressure pipe 58 through the vertical leg 65 into a duct 51 which delivers through a tube 58 and in widely dispersed form through the porous walled hollow element supported by the tube into concentric hydrochloric acid in a vessel II. The element 59 is immersed in the acid in the manner illustrated in Figure 7. The passing of the air through the concentrated hydrochloric acid forms hydrogen chloride gas by picking up hydrogen chloride which is an active deoxidizing agent. The hydrogen chloride gas passes upwardly from the vessel H and through the gas duct 12 into the gas chamber of the manifold 55.

Except for the difference in the form of the gas source, that is, the generation of gas by passing the air through the concentrated hydrochloric acid, the method practiced by use of the apparatus disclosed in Figure 7 is the same as that hereinbefore described in connection with Figures 1 through 6. The dispersion of the air in the concentrated hydrochloric acid 10 through porous element 59 causes finely divided bubbles to pass up through the hydrochloric acid, said bubbles taking up hydrogen chloride into the head space in the vessel, and the hydrogen chloride gas being delivered through the duct 12 for the can body blank deoxidizing purposes previously described. It will be understood, of course, that after the apparatus has been operated for a while, a mxiture of air and gas will pass through the duct 61 and tube 68 into the vessel II, the air being drawn through the outside slot in the manifold and the gas being drawn through the same duct 56 from the gas chamber. It will also be understood that in practicing this form of the invention, as in the case of the form of the invention previously described, a manifold 55 will be mounted at each side of the feedways over which the can bodies are fed, whether they be in a body maker structure or in a structure separate from the body maker.

As another alternative manner of practicing the invention, the duct 61 can be dispensed with and the hydrogen chloride gas generated solely by suction through the duct 56, the air and gas chambers and the duct 12, suflicient air being drawn in by suction through the tube 68 to provide for the desired generation of the gas.

In Figure 8 of the drawings there is illustrated another alternative manner of practicing the invention by use of an apparatus which includes a means for generating the gas which dispenses with the necessity of providing means for wetting the marginal edge portions of the can body blanks I before subjecting them to the cleansing or deoxidizing step. In this illustration said apparatus is shown as embodied directly in a body maker, the grain breaking station being indicated at 13, the notching station at H, and the deoxidizing station being located between the stations I3 and 14. The deoxidizing manifold equipment is generally designated 15.- The manifold is connected by a suction line 16 with the inlet of the pump 11, the outlet of the pump being connected with a pressure line 18 as in the previous disclosures. In this disclosure the pressure line 18 also includes a collecting sump 19 and delivers through a choke valve 80 and a duct 8! into a gas reclaiming vessel 82, wherein is included water as indicated at 83. A duct 8| delivers through a tube and porous walled hollow element 84 into the water, air being permitted to escape from the vessel through the outlet 85, and the gas and air mixture being dispersed through the element 84 immersed in the water so as to permit the water to absorb hydrogen chloride and reclaim the gas in the form of commercial hydrochloric acid, as previously described.

In this manner of practicing the invention the gas generating means takes the form of a vessel 83 having a hydrochloric acid and water mixture therein as indicated at 81 and being subjected to heat as at 88. The heating of the hydrochloric acid and water mixture results in the generation of a hydrochloric acid vapor and this moist gas is delivered through a gas duct 89 into the gas chamber in the manifold 15. The suction through the duct 16 serves to prevent passage of the deoxidizing gas into the atmosphere surrounding the manifold 15 in the manner previously described, and the formation of the moist gas in the manner just above described and the introduction thereof into the gas chamber of the manifold provides for the desired deoxidation of the can body blank edge portions without the necessity of wetting said edge portions previous to the introduction thereof into the manifold. In this manner of practicing the invention as in the method illustrated in Figure l, a deoxidizing manifold 15 will be mounted at each side of the body maker, and it should be understood in connection with this method, as in said other method, that separate pump and vessel sets can be provided at both sides of the body maker or single sets ma be provided with manifold connections with the individual air and gas ducts 30, 45 or 16, 89 as the case may be. It should be understood that all metal parts which are contacted by the hydrogen chloride gas in the manifold and in the pump should be made of an acid resisting alloy such as Hastelloy, tantalum, or the like.

As previously stated the invention can be practiced on various metallic body blanks or sheets whereon oxidation takes place, such as black plate, bonderized plate, or on sheets or blanks having a protective coating thereon of lacquer or enamel or both, having left bare only those marginal or edge portions which are to engage in the formation of the can body side seams. Body blanks of the last mentioned type are shown in Figures and 11 wherein the portions of the blanks having the protective coatings thereon are shaded and designated 90, and the bare marginal or edge portions are designated 9|.

While it is preferred that the novel methods be practiced by use of apparatus as disclosed herein, it is to be understood that other apparatus may be employed, and when blanks or sheets having protective coatings thereon are, being worked it will be obvious that less care need be exercised in forming the cleansing gas receiving chambers about the bare marginal edge portions of the blanks because the protective coatings are impervious to the action of the cleansing gas and portions of the coated surfaces of the blanks can be extended directly into the gas receiving chambers. When coated portions of the blanks are thus projected into the gas receiving chambers it is unnecessary to so accurately guide the blank edges, as by contact with the spacer bars IS, in order to provide cleansed areas of just the right width at the marginal edges of the blanks.

It is to be understood that the steps of the methods may be practiced by various forms of apparatus, and in various modified combinations within the spirit and scope of the invention as defined in the appended claims.

I claim:

,1. The method of deoxidizing edge portions'of travellingmetallic sheets so as to prepare them for efiicient solder bonding which comprises, feeding the sheets, forming an edge embracing chamber about said edge portions only of the travelling sheets, directing a deoxidizing hydrogen chloride gas into said chamber while the sheet edge portions are travelling therethrough, and continuously drawing air from the atmosphere surrounding said edge embracing chamber into said chamber, and air and the deoxidizing gas from said chamber and its locale thereby to prevent free passage of gas into the surrounding atmosphere.

2. The method of deoxidizing edge portions of 10 travelling metallic sheets soas to prepare them for efllcient solder bonding which comprises, feeding the sheets, forming an edge embracing i chamber about said edge portions only of the travelling sheets, directing a deoxidizing, hydrogen chloride gas into saidchamber while the sheet edge portions are travelling therethrough,

and continuously drawing air from the atmosphere surrounding said edge embracing chamber into said chamber, and air and the deoxidizing gas from said chamber and directing and dispersing the same into a confined body of water in which the hydrogen chloride will be absorbed and reformed into hydrochloric acid, the air being permitted to pass out into the surrounding atmosphere.

3. The method of deoxidizing the opposite end margins of the can body blanks which consists in feeding the blanks in horizontal position and longitudinally spaced relationship with their end margins laterally spaced and extending longitudinally, directing said end margins of each blank while travelling in said horizontal and spaced position into and through a pair of laterally spaced treating chambers shaped to closely confine said end margins and containing a deoxidizing acid gas, wetting said end margins at both upper and lower faces thereof immediately before they are directed into said treating chambers, and continuously directing a stream of a deoxidizing acid gas through each of the pair of spaced chambers while said, blank end margins are passing therethrough.

4. The method of deoxidizing the opposite end margins of the can body blanks which consists in feeding the blanks in horizontal position and longitudinally spaced relationship with their end margins laterally spaced and extending longitudinally, directing said end margins of each blank while travelling in said horizontal and spaced position into and through a pair of laterally spaced treating chambers, directing hydrochloric acid gas into said chambers while the blank end margins are travelling therethrough, and continuously drawing air from the atmosphere surrounding each said chamber into said chamber, and air and the hydrochloric acid gas from said chamber and its locale thereby to prevent free passage of the hydrochloric acid gas into the surrounding atmosphere.

5. The method of deoxidizing the opposite end margins of the can body blanks which consists in feeding the blanks in horizontal position and longitudinally spaced relationship with their end margins laterally spaced and extending longitudinally, directing said end margins of each blank while travelling in said horizontal and spaced position into and through a pair of laterally spaced treating chambers, wetting said end margins at both upper and lower faces thereof immediately before they are directed into said treating chambers, directing hydrochloric acid gas into said chambers while the blank end margins are travelling therethrou'gh, and continuously drawing air from the atmosphere surrounding each said chamber into said chamber, and air and the hydrochloric acid gas from said chamber and its locale thereby to prevent free passage of the hydrochloric acid gas into the surrounding atmosphere.

ALFRED L. KRONQUEST.

(References on following page) 11 REFERENCES CITED Number The following references are of record in the 2'055934 file or this pal-tent: UNITED STATES PATENTS 2:288:980 Number Name Date 2,305,655 57,738 Llpps Sept. 4, 1866 2,326,814 165,050 Allen June 29, 1875 2,347,527

1,375,663 Ainsworth Apr. 26, 1921 12 Name Date Kronquest Sept. 29, 1936 Grupe Sept. 26,1939 Seaton Nov. 5, 1940 Turin July 7, 1942 Woolford Dec. 22, 1942 Wobbe Aug. 17, 1943 Vanderbilt Apr. 25, 1944 

1. THE METHOD OF DEOXIDIZING EDGE PORTIONS OF TRAVELLING METALLIC SHEETS SO AS TO PREPARE THEM FOR EFFICIENT SOLDER BONDING WHICH COMPRISES, FEEDING THE SHEETS, FORMING AN EDGE EMBRACING CHAMBER ABOUT SAID EDGE PORTIONS ONLY OF THE TRAVELLING SHEETS, DIRECTING A DEOXIDIZING HYDROGEN CHLORIDE GAS INTO SAID CHAMBER WHILE THE SHEET EDGE PORTIONS ARE TRAVELLING THE THEREGHROUGH, AND CONTINUOUSLY DRAWING AIR FROM THE ATMOSPHERE SURROUNDING SAID EDGE EMBRACING CHAMBER INTO SAID CHAMBER, AND AIR AND THE DEOXIDIZING GAS FROM SAID CHAMBER AND ITS LOCALE THEREBY TO PREVENT FREE PASSAGE OF GAS INTO THE SURROUNDING ATMOSPHERE. 